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Development of forest trees with enhanced drought tolerance

Improving
selection by combining physiological and morphological methods for examination
of trees responses to drought under controlled conditions and in the field

Global climate-change scenarios in the Mediterranean region forecast rising
temperatures, reduced rainfall amounts and a generally drier climate. The
rapidly changing climatic conditions might put perennial species, particularly
trees, in danger because of their inherent slow adaptation rates.
For afforestation in drylands under a changed climate, there is a need for more
drought tolerant trees.

This study focusses on a combination of physiological
and morphological methods for selection of genotypes with enhanced drought
tolerance. Model tree species used for afforestation in Israel are the evergreen
conifer Aleppo pine (Pinus halepensis) and the deciduous broad-leaved Atlantic
pistachio (Pistacia atlantica). Mother trees showing features of adaptation to
drought in dry southern Israel serve as seed sources for this project. Seeds of
each mother plant are evaluated for indices of drought tolerance by three
different approaches:

1) transpiration under drought treatment as assessed by
lysimeters on the whole-plant level;

3) growth rate of an efficient root
system as assessed under standard and drought conditions.

Drought tolerance of
seed sources tested under controlled conditions will also be evaluated in the
field. The findings of this project will assist in selecting drought tolerant
seed sources for afforestation under a future drier climate. In addition, the
studies will deepen our understanding in the ecophysiological and morphological
processes related to drought tolerance in trees.

Collaboration: Rony Wallach, the Hebrew University of Jerusalem, Rehovot, Israel
Menachem Moshelion, the Hebrew University of Jerusalem, Rehovot, Israel

Co-workers: Dana Sarid (MSc student)

Partner organizations: Ministry of Agriculture and Rural Development KKL –
Jewish National Fund